Sample processing in immunohistochemical (“IHC”) applications, for example, and in other chemical and biological analyses may involve one or a number of various processing sequences or treatment protocols as part of an analysis of one or more samples. Typically, such treatment protocols are defined by organizations or individuals requesting analysis, such as pathologists or histologists attached to a hospital, and may be further defined by the dictates of a particular analysis to be performed.
A fluorescence in-situ hybridization (FISH) procedure is traditionally a two days manual procedure. Attempts have been made to automate parts of the procedure in order to shorten the processing procedure and to reduce the number of manual steps. For example, the first day pre-treatment procedure has been automated with an instrument VP2000™ (Vysis, Abbott Molecular), in which instrument a robot moves slides from one jar to another. However, the problem so far has been to combine the pre-treatment steps of the first day and the washing steps of the second day with the strict physical and environmental requirements of the denaturation and hybridization steps in between. In these steps it is preferred to use small volumes of processing liquids and provide a precise control of the humidity in the processing chamber surrounding the processed tissue section, and to provide controlled heating and cooling in order to obtain consistent FISH results.
Automated IHC and ISH staining instruments have been introduced by Ventana Medical Systems Inc. (BenchMark™ and Discovery™) and VisionBiosystem (Bond™). A drawback with these instruments is that they only provide a fixed processing volume, i.e. the processing chamber is of a fixed volume. The processing chamber volume in the instrument being at least 100 micro liters.
The BenchMark™ instrument, having a capacity to process 30 slides, needs to cover the tissue section to be processed and the applied processing liquid with oil in order to reduce evaporation of the processing liquid. If not covered by oil, the evaporation of processing liquid will deteriorate the processing result.
The Bond™ instrument, having a capacity to process 30 slides, has a small processing chamber which is clamped over each tissue section and each carrier. By clamping the processing chamber over each carrier, an individual staining cavity is created.
Some of the drawbacks with prior art instruments are that they require relatively large volumes, about 150-200 micro liters, of processing liquid, that they do not provide as good results as manual processing, and that they do not provide a variable volume of processing liquid to be used by providing a processing chamber having a variable volume.
An aim of the present invention is to solve these and other problems and drawbacks with the prior art system.
For example, an object of the present invention is to provide processing of a biological sample arranged on a carrier using a small quantity of processing liquid.
Another object of the present invention is to provide processing of a biological sample arranged on a non-horizontal carrier.
Yet another object of the present invention is to provide a processing apparatus for processing of a biological sample arranged on a carrier, the processing apparatus being configured to provide a variable volume for processing liquid.
Another object is to provide automated processing of a biological sample arranged on a carrier using a small quantity of processing liquid.